This disclosure relates to a structural component of a vehicle such as a lift gate, and in particular, a polymeric vehicle component.
Structural components for vehicles, such as front end modules and lift gates, can be loaded with torsion due to forces acting at separate locations. To accommodate this, high bending stiffness is desirable. For some applications, techniques such as injection molding and/or injection compression molding, such as with a given drawn direction and sliders, cannot provide desired and/or sufficient torsion stiffness.
Lift gates are provided to open or close an opening formed in a vehicle (e.g., at a rear portion of a hatch back type of passenger vehicle or the like). Front end modules are provided to allow access to components in the front of a vehicle, such as a truck. For example, components including cooling systems and oil and wiper fluids, and possibly other components (e.g., engine, radiator, heating, ventilation, and air conditioning systems) might be accessed through a front end module of a truck or bus. Because the weight of a vehicle body has an impact on the fuel consumption of the vehicle, attempts have been made to produce lift gates and front end modules from lighter-weight materials, such as polymeric materials, in an effort to reduce the overall weight of the vehicle. The use of polymeric materials reduces the overall weight, but in some applications may not accommodate stresses and strains placed on the lift gate or front end module. As an example, the lift gate or front end module may bend undesirably. This can displease a consumer. Worse yet, such flexure may fail to sufficiently resist deformation in a crash.
Lift gates and front end modules are large component members of a vehicle body that rotate around a hinge when they open or close. Due to the level of stress from the repeated opening and closing of the components and the size of the components, they comprise a lot of metal (for structural integrity) and have ribs or steel inserts to ensure proper operation and structural stability. Other attempts to increase the stiffness and torsional rigidity include increasing the thickness of the panels. However, an increase of the panel thickness and/or the addition of the ribs for increasing the rigidity of the component also increases the overall weight of the component, which can negatively affect the fuel efficiency of the vehicle. Furthermore, the use of reinforcements, such as ribs, can affect the ability to efficiently run wires, cables, or the like through the component. In addition, ribs and other reinforcements negatively impact the aesthetic quality of the component because such features can leave visible imperfections on the panels, thus requiring an additional panel to be installed to provide a finished appearance. The use of steel or other materials in combination with a plastic component can also add manufacturing time and expense to the production of the vehicle component.
Accordingly, a need exists for a light-weight vehicle component with high torsional and bending stiffness without diminishing the functional and/or aesthetic quality of the component.